I'm getting short of space on my PC's system drive (e: ) and would like to move my iPad backup to my much larger data drive (f: ).

Is there any way to do is from within iTunes? Or perhaps by manually transferring the files with Windows Explorer, then telling iTunes where the new storage folder is located?

Would prefer if I could automatically save future backups to the data drive. Is there any way to change the default storage folder that iTunes uses?

A simple answer is to upgrade your internal hard drive after backing up or cloning it after restore t.hen you have room and problem resolved. You can move the iTunes folders and make changes in iTunes to point at the other drive .

Having just upgraded my data drive, I'm not really inclined to upgrade my system drive as well.
I don't have the money to upgrade every component in my PC, plus it's quite a fiddly and longwinded job changing out hard-drives and cloning them.
It really shouldn't be necessary to change hardware components for something like this; there ought to be a way of doing it from the iTunes software.

N.B. In the second part of your answer you seem to imply that there is a way to relocate the storage folders within iTunes; but you haven't said how? Where do I find the menu options to do this?

Try this link ok

iTunes for Windows: Moving your iTunes Media folder

You can change the location of iTunes' media folders, but I do not know of any way to change the backup. However; the backup is by far the smaller concern. It does not include your music, movies, or other large files. Only some settings, events, and third party app data. Of course, if you are storing movies in third party apps, that could get bulky.

Oops, wrong link. Try again.

http://support.apple.com/kb/HT4079

Thanks for the links.

Unfortunately the backup doesn't contain any media.
I don't have any music or movies on my iPad, and I don't think it backed-up my photos either (I turned off photo-syncing in iTunes settings, and presumably this affects back-ups too?)

What's using up the disk space is a large data cache in one of my app.s. It's eating up about 5 GB on my system drive.

Looks like I'm out of luck then: I'll just have to risk not backing up my iPad.
Insane that there's no iTunes setting to solve this! After all most people's PC's have small system partitions and large data partitions.